Western Australia recorded the strongest growth in registered births and fertility in Australia in 2004. This followed three years where the number of births in the state were relatively low and the fertility rate had fallen to below that recorded nationally.

The following analysis provides insight into the variability of births and fertility in Western Australia over recent years. Important longer term trends are also presented to provide context and where relevant similarities and differences between state and national level are discussed.

INTRODUCTION

The fertility of the population can be measured by the rate at which women bear children. The rate of child-bearing by women has been declining in Western Australia and nationally since 1961, the height of the post war baby boom in Australia. This decline stems from a number of significant social changes including the introduction of oral contraception, increased access to abortion, changes in family formation and increased education and employment opportunities for women.

A major consequence of the decline in fertility has been the ageing of the population. This phenomenon has received widespread attention in recent years due to its potential impact on the workforce and the caring capacity of the population in the future.

Over the past few years a number of government initiatives have been implemented aimed at encouraging women and their partners to consider having a first or additional children. Perhaps the most well known of these was the Federal Government's introduction of the new Maternity Payment of $3,000 paid to parents of babies born after 1 July 2004. There has been insufficient time for the Maternity Payment to have contributed to any recorded changes in births between 2003 and 2004.

BIRTH AND FERTILITY MEASURES

A number of factors are generally used to measure fertility. For this analysis the focus has been on the following:

The number of registered births, being the total births registered during each calendar year.

The size of the female population aged 15 to 49 years at 30 June each year. These ages are considered to be the reproductive years for women;

The total fertility rate (TFR) which represents the number of children a female would bear during her lifetime if she experienced current age specific fertility rates at each age of her reproductive life; and

Age-specific fertility rates (ASFR) which represent the number of live births according to the age of the mother per 1,000 of the female estimated resident population of the same age at 30 June in each year. Age specific fertility rates are calculated for women aged 15 to 49 years.

FERTILITY TRENDS IN WESTERN AUSTRALIA

Over the period 1971 to present, some important trends have emerged in relation to births and fertility in Western Australia. These include:

Sustained growth in the number of registered births between 1979 and 1991, followed by a number of years where births fluctuated within a relatively narrow band (24,700 and 25,400);

Strong growth in the female population aged 15 to 49 years until the early 1990s before tapering off in subsequent years;

A gradual decline in Western Australia’s TFR; and

A steady increase in the age at which women have been bearing children.

Registered births

In 1971, Western Australia recorded a peak in the number of births registered (24,300) to that point in time, but this was followed by a short period of decline then relative stability between 1974 and 1979. Following this period there was a prolonged period of growth in the number of registered births until they reached a high of 25,400 in 1991. Since then the annual number of births registered in Western Australia has fluctuated within a relatively narrow band (between 24,700 and 25,400), with the exceptions of 2001 (24,000), 2002 (23,600) and 2003 (24,300) when they were historically low.

While births in Western Australia have exceeded the 1971 mark in most years since 1988, nationally the peak of 276,400 reached at this time has not been matched again. Notably, the decline in births following 1971 was for a shorter period and less pronounced at the state level than nationally and the increase from the late 1970s to the early 1990s was more substantial. Throughout the 1990s the number of births in Western Australia was relatively stable but they declined steadily at the national level.

1. REGISTERED BIRTHSSource: ABS data available on request, Births.

Female population aged 15 to 49 years

There were 251,000 women aged 15 to 49 years in Western Australia in 1971. By 2004 this population had increased to 500,000, an overall increase of 99.4% and annual average growth of 2.1%.

Between 1971 and 1991 there was a marked increase in the population of women aged 15 to 49 years (74.9% or 2.8% annually). This growth was due to later born baby boomers (1956-1965) progressively moving into these ages and strong net migration to Western Australia during this period. These factors influenced the steady increase in the number of births in Western Australia between 1979 and 1991 despite the declining fertility rates over the period.

In comparison, the population growth of women aged 15 to 49 years has been more moderate in Western Australia between 1991 and 2004 (14.0% or an average or 1.0% per annum). As a result any impact population growth may have had on the number of registered births at the state level has been less discernible over this period.

At the national level, the female population aged 15 to 49 years did not experience the same rate of growth (60.5% or on average 1.4% per annum) as in Western Australia between 1971 and 2004. With this being the case the potential for growth in registered births has been more limited nationally than in Western Australia.

2. FEMALE POPULATION, 15 to 49 YEARS

Fertility rates

Changes in the TFR over the past 30 years indicate that women in Western Australia are having fewer children. From 1975, the TFR fell by 20.4% from 2.18 to 1.81 births per woman. Notably, the state’s TFR fell below 2.10, the rate required for replacement of the population in 1977. This is defined as the number of babies that a female would need to have over her reproductive life span to replace herself and her partner.

The decline in the TFR in Western Australia has followed much the same pattern as for Australia as whole. However, in most years since 1971 the rate has been slightly higher in Western Australia than at the national level. The gap between the state and national TFR was generally widest from the mid 1970s through the 1980s but there has been convergence in the period since. Atypically, the TFR for Western Australia fell below the national rate in 2001, 2002 and 2003.

3. TOTAL FERTILITY RATE(a)

Age-specific fertility

The age at which women in Western Australia are having children has been increasing. The median age of mothers increased from 25.3 years in 1975 to 30.2 years in 2004. There has also been steady growth in the fertility rates of women aged 30 years and over while the rate among younger women has declined. Since 2002, the 30-34 year age group has had the highest fertility rate in Western Australia surpassing fertility recorded for those aged 25-29 years.

4. AGE-SPECIFIC FERTILITY RATES(a)

These trends are much the same as those which have occurred at the national level. However, there have been higher fertility rates for younger women between the ages 15 to 24 years and marginally lower rates for women above 30 years in Western Australia.

Aboriginal and Torres Strait Islander fertility

One factor impacting on the younger age of mothers in Western Australia relative to Australia is the higher proportion of Indigenous people in the state. Indigenous women have higher fertility rates compared to the total population and are more likely to have children at younger ages.

In 2004, the TFR of Indigenous women in Western Australia was 2.29 births per woman, compared with 1.81 for all women. Similarly, the median age at the time of giving birth of Indigenous mothers in Western Australia was 24.1 years compared with 30.2 years for all mothers.

5. AGE-SPECIFIC FERTILITY RATES (a), Western Australia-2004

RECENT FERTILITY TRENDS IN WESTERN AUSTRALIA

In recent years (1999 to 2004) the fertility rates and number of births registered in Western Australia have fluctuated considerably while the female population aged 15 to 49 years has only increased slightly. Recent trends include:

The state’s female population aged 15 to 49 years increased by 3.6% between 1999 and 2004 to 500,000;

Registered births in Western Australia fell to a low of 23,600 in 2002 but reached a near record high of 25,300 in 2004;

The state TFR fell below the national rate in 2001, 2002 and 2003, with a low of 1.70 births per women recorded in 2002;

Fertility was lower but less variable in the Perth statistical division (SD) than for the rest of the state; and

There has been greater fluctuation in the number births and the total fertility rate in Western Australia than for Australia.

Registered births 1999 to 2004

There was a large decline in the number of births registered (4.3% or 1,100 births) between 2000 (25,100) and 2001 (24,000). In 2002, registered births declined further to 23,600, their lowest number since 1987. Although births increased to 24,300 in 2003 the number registered remained historically low.

The number of births in Western Australia continued to rebound in 2004 reaching 25,300. This was the third highest number of births recorded in the state (only exceeded in 1990 and 1991) and represented an increase of 4.2% (1,000 births) compared with the previous year. Notably, the increase in births registered in 2004 represented one-third of the national increase of 3,100 births.

At the national level there was also some variability in the number of births over this period but not to the same extent as in Western Australia. Nationally, births dipped noticeably in 2001 (246,000) but have since increased.

6. REGISTERED BIRTHSSource: ABS data available on request, Births.

Fertility 1999 to 2004

The annual changes in the number of births to Western Australian women have contributed to the variability in the fertility rate in recent years. The TFR in Western Australia fell noticeably in 2001 to 1.73 births per women and the lowest rate on record occurred in 2002 when the TFR was 1.70 births per women.

While the TFR increased in 2003 to 1.74 births per women, it remained below the national rate for the third consecutive year. In 2004, the TFR in Western Australia (1.81 births per women) increased by 3.8% compared with the previous year and again rose above the national rate (1.77 births per women).

7. TOTAL FERTILITY RATE(a)

In 2001, when the Western Australian TFR fell below the national rate for the first time in 10 years, the state age-specific fertility rates declined for women in all five year age groups under 40 years. Notably, this included a fall in the fertility of those aged 30-34 years (3.3%) and 35-39 years (0.9%) which was contrary to the long term trend of increasing fertility for these age groups.

The decline in the fertility of younger Western Australian women (aged 15-19 and 20-24 years) from 2000 to 2001 was considerable and was followed by less substantial falls in 2002 and 2003. Although the fertility rates for women in these age groups continued to be higher in Western Australia than nationally, the gap closed noticeably over this period compared with previous years.

In 2004, when Western Australia experienced relatively strong growth in the number of births and the TFR returned above the national rate, fertility increased for women from all age groups (except 45-49 years) compared with the previous year. Between 2003 and 2004 the age-specific fertility rate of women aged 30-34 years increased by 4.5% from 109.5 to 114.4 births per 1,000 women. As a result the fertility rate for Western Australian women from this age group equalled the national rate for the first time in 30 years.

The increase in fertility for younger age groups in Western Australia between 2003 and 2004 was 5.9% for those aged 15-19 years and 4.6% for those aged 20-24 years. At the national level, fertility rates for these age groups continued the long term trend of decline.

9. CHANGE IN AGE-SPECIFIC FERTILITY RATES (a), 2003 to 2004

Recent trends show that fertility has been lower but less variable for women from the Perth statistical division than those residing elsewhere in the state. The average fertility rate for Perth was the same for the periods 1999-2001 and 2002-2004 (1.67 births per women). In contrast, the average fertility rates for the remaining statistical divisions in Western Australia were on average lower for the period 2002-2004 than for 1999-2001.

10. TOTAL FERTILITY RATE(a), Statistical Divisions-Western Australia

Collection issues

The annual number of births registered in Western Australia include a proportion of births that occurred in previous years. From year to year this proportion may vary due to timing issues, administrative changes or processing delays. Such variation can contribute to fluctuations in the number of births recorded and therefore affect the TFR. This issue is avoided in another source of birth data in Western Australia, the Midwives Notification System (MNS), because it records information about births that occurred in a given year.

Over the period 1999 to 2004, the MNS data show a smoother but similar trend in births and fertility to the ABS registered birth series. This suggests annual fluctuations in the proportion of births from previous years may have contributed to the recent variability in registered births and fertility discussed in this article. However both collections indicate a sharp rise in the number of births in 2004.

11. Births, Western Australia, Western Australia

Midwives (MNS) births

Registered births

Year

No.

Total fertility rate(a)

No.

Total fertility rate(a)

1999

25 581

1.843

24 849

1.788

2000

25 000

1.801

25 093

1.807

2001

24 761

1.781

24 002

1.726

2002

24 592

1.771

23 601

1.698

2003

24 478

1.756

24 273

1.741

2004

25 314

1.808

25 295

1.807

(a) Birth per woman.

Sources: Western Australian Midwives Notification System; ABS data available on request, Births.

CONCLUSION

Over the last three decades the fertility of women in Western Australia has been steadily declining and the age at which they bear children has gradually increased. Notwithstanding this general trend, the number of registered births and fertility rates in Western Australia have fluctuated considerably in recent years.

In 2001, 2002 and 2003 the number of births registered in Western Australia were historically low and the TFR, uncharacteristically, fell below the national rate. In contrast, the state recorded strong growth in the number of registered births in 2004 (4.2%) and accounted for one-third of the increase at the national level. The TFR for Western Australia also rose for the second consecutive year in 2004 to again be above the national rate. While these changes provide evidence of increased fertility in Western Australia in the short term, it is still too early to determine with certainty whether the long term trend of declining fertility in Western Australia has actually halted.